Field of the Invention
The present invention relates to wireless communication, and more particularly, to a method for operating a terminal for supporting interworking between heterogeneous networks in a wireless communication system and a terminal using the same.
Related Art
3GPP (3rd Generation Partnership Project) LTE (long term evolution), a development of UMTS (Universal Mobile Telecommunication System), was introduced in 3GPP Release 8. 3GPP LTE uses OFDMA (orthogonal frequency division multiple access) for the downlink and SC-FDMA (Single Carrier-frequency division multiple access for the uplink. Recently, there have been discussions about 3GPP LTE-A (LTE-Advanced), which is an evolution of 3GPP LTE.
A wireless communication system may have support for services to UEs over multiple access networks. For example, a UE may receive service from a 3GPP access network, which is a wireless communication system, and also may receive service from a non-3GPP access network, such as WIMAX (Worldwide Interoperability for Microwave Access) or WLAN (Wireless Local Area Network).
A UE may establish a connection with a 3GPP access network to receive a service, and if traffic overload occurs to the 3GPP access network, may handle the traffic over another access network, i.e., a non-3GPP access network, to improve the overall network efficiency. Reversely, a UE connected to a non-3GPP access network may handle traffic using a 3GPP access network for efficiency.
Suppose that there are two different networks: a first network and a second network. Interworking refers to the ability of a UE connected to the first network to access and use resources or services offered by the second network. In the conventional art, the UE is given predetermined rules for interworking and performs interworking according to these rules. That is, a network informs the UE of interworking rules, and the UE performs interworking by itself.
On the other hand, Recently, there have been recent attempts to control interworking in a network. In order for a network to control interworking, it is important to know the communication status between other networks and a terminal are going on, QoS (Quality of Service), etc. For example, it is assumed that a first network and a second network work together to provide a service to a terminal connected to the first network. In this case, the QoS provided and guaranteed by the first network and the QoS provided and guaranteed by the second network may different. If the quality of service provided by the second network does not satisfy the QoS required for the corresponding service, the first network may have to take action to resolve this problem. However, the conventional art has the problem that, when heterogeneous networks interwork, the communication status, QoS, etc. of a certain network are not know to the other networks.